The Stovebolt Site Forums The Parking Lot Big Bolts Post '63 Big Bolt Axle Discussion

So it would appear that it is time for the next question. I have a route for engine and trans, and have located 2 wheels to start with, but now I move onto axles. Starting with the front.

Ripped apart the front to find a seized wheel cylinder and heavily worn bearings. As I dismantled I shook the spindles an in doing so I heard the tell-tale sound of the king pins knocking around. It isn't "bad" but its not great. If I am going to rebuilt an axle, may as well make it a better axle with higher load cap since I plan to re-power to a heavier motor anyways. Im on the hunt in the junkyards for an axle of higher load rating now. Is there an easy way to identify axles under a truck by AWR at all? It would be best to identify by bearing size/bore but very hard to do in a junkyard, so there has to be an easier way. All these trucks seem like someone just threw darts at a board and wherever they landed dictated engine/axle/GVW/etc so trying to find a specific model may not pan out since all the models are inbred to a degree.

As for rear, I am on the hunt for a single speed, high ratio, higher load rating rear, preferably with a different (more common) lug pattern (corresponds to the desired engine). This is where things get even more confusing though. How do the axles from, say a 70's-80's era c70 compare with the old eaton 2 speed? Square tube vs round tube? I am already accounting for a custom drive shaft work, so can it be assumed that an axle is an axle is an axle, find one closer to the 26k lb load and stick it under? If so, I may try to steal the matching front axle to keep lug patterns similar across both.

Any input on donor trucks for similar WMS and the such? Other than some fab work and elbow grease, any perceived issues with this thought process? The '64 is the standard 34" frame width like every other mid-size out there so the only issue I could see on the axles is spring width. Course, springs would be swapped with axles too for proper load capabilities. I would grab the whole steering setup with whatever front axle I grab as well and adapt as required

In the end, im not building a 38K lb GVW dump truck, but im a firm believer that a little bit overkill is safer and goes a long way when considering pretty constant standard "heavy" load almost. Plus im adding in almost 1500lb worth of motor and trans in the re-power, so its now "justifiable" to the wife.

What engine are you planning on using? There are directions on here in using a GM 2 ton front axle, adding GM P-30 spindles. If you want a wider front axle, modern GM P-30 and 3500 have heavy capacity front axle with ff 14 bolt or D-70/80 rear for which higher ratios/disc brakes are available.

Ed

Engine planned is a detroit 2 stroke, so there will be some heft. I have dug, but the info I have seen thus far that you are referring to is below the weight class im looking at (please correct me if I am wrong). The current setup is a 15k rear with 5k front. The front could easily handle the engine, but it would be pushing it with engine + load. So in my head, between re-power, expected load, and then full axle rebuild, may as well swap and shoot for a 7-11K class front axle to put the money into.

Similarly with the rear, the current 2 speed gearing would be far from optimal with a narrow power band diesel, so swapping to a batter highway geared single speed would be optimal. Thus I wont bother sinking any money into this eaton in favor or just replacing it with something in the 19k class.

End state would push toward the 26K GVW which is great and possibly wont restrict the wheel style based on axle choice, which would allow a taller 22.5 for highway travel that's easily and cheaply sourced and commonality with the other trucks on the farms. The hardest part is simply trying to ID axles from a junkyard to try and determine weight classes (particularly fronts).

Your best shot may be to buy a complete diesel truck chassis and swap everything over to your frame. That way you get matching wheel lug pattern and the right rear ratio and maybe even the right transmission...might be way cheaper this way! You might even score a good set of rims and tires as well...

As a bonus you might find an air brake truck and get all the needed parts for that swap as well.

Don't over look school buses in you travels.

Mike B

I agree with Mike B above. I put GMC P-3500 running gear, power brake, power steering, disc brake axles, 4-53T in my '37 GMC, everything is happy together.

If you keep the GVW under 26,000 you will not need a CDL.

Ed

Not a bad idea at all actually, especially with an air system. I had been looking at 80's era c70's (mostly gassers) as a donor, but it would make more sense to dig at say an old international with a D466 or something of similar style. Most all medium/heavy trucks run the 34" frame width correct? The only real difference I possibly see is spring widths, but that could be adapted I would think, or just run a different dimension pack with similar load cap. Thus one wouldn't be limited to only GM vehicle donors right?



I believe that you have some threads out there about that correct? I know Grigg does as well, and I have become quite intimate with said threads across a multitude of forums. Also I am not too worried about the CDL cutoff. The truck will get a farm plate and be used to haul "farm commodities" and the such mostly, and no CDL is required for farm plates regardless of weight here in Indiana.


*Edit*
Come to think of it, most manufacturers sourced axles from the same company right? Its why Eatons are under GM, Ford, International, etc. Thus regardless of make/model of donor (to an extent), axles should be a pretty simple swap over and use similar spring setups. Again the difference from the '64 frame to say a '80-ish frame may be wider leaf springs, but the axle should be capable of mounting to a thinner width, thicker pack for the same load. Obviously ignoring steering and rear yoke, everything should be a simple bolt in then and it merely comes down to what kind of breaks are desired (disc, drum, air). Can it really be that simple? Or am I overlooking something?

GM tapers the front frame at the front, others may also. On my '37 frame, I found some longer springs( for a better ride) from similar weight vehicle, two leaf setup, and anchored spring at front instead of rear(for a better ride, again) which required offset to make springs parallel, new shackle mount(at rear) straddled frame as normal.

Sounds more complicated than doing it.

Ed

They tapered the frame on the AD and earlier trucks, but I'm pretty sure they went parallel in 55.2

I will check the front frame on Saturday when I am back in the shop to verify. From the time I have spent underneath, I am pretty sure the 34" width is maintained up thru the front end.

Not thought of until now, newer fronts may have a wider WMS. Clearly more narrow would be a problem, so wider isn't bad I would think, it may just push the wheels outside the fenders a bit. Far as I know, theres no law against that.

It is against the law to have tires sticking outside the fenders, even though it is not enforced much, other than flinging mud and other debris on your vehicle, it works. Some on here have cut and welded solid axle, others have narrowed center section of IFS axle. Still others have spaced fenders out with spacer blocks if fenders are not attached('30's GMC)

Ed

Good to know on that. Im not above cutting and welding if need be. Ill take some more measurements and then disappear back out into the junkyard for a day and just dig to see what I can turn up.

It's a lot simpler and less expensive to alter sheet metal than it is to narrow an axle. Adding a couple of inches of fender width on each side will cover the tires a lot more effectively and won't do dangerous things to steering geometry, and your local body shop guy doesn't have to be a suspension engineer to make things look good.
Jerry